Optimizing shadow generation by reusing bitmap.
> Not creating unnecessary bitmaps
> Final bitmap is generated as ALPHA_8 instead of ARGB_8888
> The shadow drawing is done directly in the view
Change-Id: I504fa2ea3abdc1a3c3fb9ad57d6e28880d2584a1
diff --git a/src/com/android/launcher3/ClickShadowView.java b/src/com/android/launcher3/ClickShadowView.java
new file mode 100644
index 0000000..42fafe2
--- /dev/null
+++ b/src/com/android/launcher3/ClickShadowView.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.launcher3;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.view.View;
+import android.view.ViewGroup;
+
+public class ClickShadowView extends View {
+
+ private static final int SHADOW_SIZE_FACTOR = 3;
+ private static final int SHADOW_LOW_ALPHA = 30;
+ private static final int SHADOW_HIGH_ALPHA = 60;
+
+ private final Paint mPaint;
+
+ private final float mShadowOffset;
+ private final float mShadowPadding;
+
+ private Bitmap mBitmap;
+
+ public ClickShadowView(Context context) {
+ super(context);
+ mPaint = new Paint(Paint.FILTER_BITMAP_FLAG);
+ mPaint.setColor(Color.BLACK);
+
+ mShadowPadding = getResources().getDimension(R.dimen.blur_size_click_shadow);
+ mShadowOffset = getResources().getDimension(R.dimen.click_shadow_high_shift);
+ }
+
+ /**
+ * @return extra space required by the view to show the shadow.
+ */
+ public int getExtraSize() {
+ return (int) (SHADOW_SIZE_FACTOR * mShadowPadding);
+ }
+
+ /**
+ * Applies the new bitmap.
+ * @return true if the view was invalidated.
+ */
+ public boolean setBitmap(Bitmap b) {
+ if (b != mBitmap){
+ mBitmap = b;
+ invalidate();
+ return true;
+ }
+ return false;
+ }
+
+ @Override
+ protected void onDraw(Canvas canvas) {
+ if (mBitmap != null) {
+ mPaint.setAlpha(SHADOW_LOW_ALPHA);
+ canvas.drawBitmap(mBitmap, 0, 0, mPaint);
+ mPaint.setAlpha(SHADOW_HIGH_ALPHA);
+ canvas.drawBitmap(mBitmap, 0, mShadowOffset, mPaint);
+ }
+ }
+
+ public void animateShadow() {
+ setAlpha(0);
+ animate().alpha(1)
+ .setDuration(FastBitmapDrawable.CLICK_FEEDBACK_DURATION)
+ .setInterpolator(FastBitmapDrawable.CLICK_FEEDBACK_INTERPOLATOR)
+ .start();
+ }
+
+ /**
+ * Aligns the shadow with {@param view}
+ * @param viewParent immediate parent of {@param view}. It must be a sibling of this view.
+ */
+ public void alignWithIconView(BubbleTextView view, ViewGroup viewParent) {
+ float leftShift = view.getLeft() + viewParent.getLeft() - getLeft();
+ float topShift = view.getTop() + viewParent.getTop() - getTop();
+ int iconWidth = view.getRight() - view.getLeft();
+ int iconHSpace = iconWidth - view.getCompoundPaddingRight() - view.getCompoundPaddingLeft();
+ float drawableWidth = view.getIcon().getBounds().width();
+
+ setTranslationX(leftShift
+ + view.getCompoundPaddingLeft() * view.getScaleX()
+ + (iconHSpace - drawableWidth) * view.getScaleX() / 2 /* drawable gap */
+ + iconWidth * (1 - view.getScaleX()) / 2 /* gap due to scale */
+ - mShadowPadding /* extra shadow size */
+ );
+ setTranslationY(topShift
+ + view.getPaddingTop() * view.getScaleY() /* drawable gap */
+ + view.getHeight() * (1 - view.getScaleY()) / 2 /* gap due to scale */
+ - mShadowPadding /* extra shadow size */
+ );
+ }
+}